In recent years, electric vehicles using an electric motor as a drive source as well as so-called hybrid electric vehicles using a combination of an electric motor and another drive source such as an engine have been practically available. This kind of vehicle is equipped with a power storage unit for supplying energy, i.e., electricity to the electric motor. The power storage unit is formed of a capacitor or a repetitively rechargeable secondary battery such as a nickel-cadmium battery, nickel-hydrogen battery or lithium ion battery. The power storage unit is accommodated in a casing, and is mounted on the vehicle as a power storage device.
Japanese Patent Laying-Open No. 2005-247064 has disclosed a mounting structure of a power storage mechanism that has a cable located under a floor panel. In this mounting structure, the cable extends through an opening formed in the floor panel, and is attached to a battery-side terminal of a battery pack from its lower side. A shield cover is attached to the floor panel form its lower side, and covers the cable from the lower side. According to the disclosure, this mounting structure of the power storage unit does not require designing of positions and forms of units such seats in a cabin and a spare tire in a luggage room in view of a space for arranging the cable, and flexibility in design can be increased.
“Manual of New Model Car Prius” (issued on Sep. 1, 2003) has disclosed a structure of mounting a battery pack with its longitudinal direction parallel to a width direction of the vehicle. This battery pack includes a unit casing containing a battery computer. The unit casing is arranged on an end surface of the battery pack. The unit casing is faced toward a side in the vehicle. A cable supplying electricity for driving the motor protrudes from this unit casing toward the side in the vehicle for connection.
In recent years, electric and hybrid electric vehicles, and particularly the hybrid electric vehicles have been widely spreading. With increase in demand for the hybrid electric vehicles, the number of types of the hybrid vehicles has been increasing.
The battery pack disclosed in the foregoing manual of new model car Prius is arranged such that its longitudinal direction is parallel to the width direction of the vehicle. The cable connecting the battery accommodated in the battery pack and an inverter extends through the side surface of the battery pack.
Sizes of the power storage device primarily depend on a capacitance and output voltage of the power storage unit. Therefore, a longitudinal size of the power storage device may increase. For example, when the power storage device is arranged with its longitudinal direction parallel to the width direction of the vehicle as described above, the battery cable protruding sideways may be pressed against a body. Also, another problem may occur and, e.g., the power storage device cannot be arranged without difficulty. As described above, arrangement of the power storage device has been restricted, and the power storage device of which arrangement is less restricted has been required.